2.74 ADH

Key Points:
1. ADH = Anti Diuretic Hormone. ADH is produced in the hypothalomus of the brain. This flows through the blood stream and targets the kidney.
2. The effect of ADH is to control and alter the composition of water which is in blood. ADH has the ability to make the blood more or less concentrated. This is important because of the dangers of not having isotonic status.
3. ADH targets the collecting duct, where the water goes out, and the effect of ADH is that it allows more water to exit the collecting duct.
4. The collecting duct is responsible for the recycling of blood back into the bloodstream. ADH makes the collecting duct walls more porous, so the water can escape easier.
5. The consequence of the ADH secretion is that the urine would be more concentrated with a less volume. ADH secretion causes this.

On a hot day we lose water through sweat, and this means less water will be in the blood when it goes to the kidneys for ultrafiltration. As there is less water already, the ADH response would most likey be more than usual, causing us to retain more water and recycle it back into the blood stream. This is probably amplified with dehydration, as the loss of water through urine may be a life/death scenario, so it is probably likely that the ADH will have a greater effect upon the recycling of water, and more water will re-enter the bloodstream so that our bodies can keep going.
This is probably the opposite with a cold day.